Swimming is a skill primarily used in the wilderness, although certain non-wilderness areas employ it, as well. A character can swim in every compass direction as well as up or down; swimming down takes them underwater, while swimming up brings them closer to the surface. A character who does not hold their breath underwater, who cannot swim well, or who loses consciousness in an area which requires swimming risks injury and eventual death by drowning.

A character will automatically start swimming when they enter a water tile on the wilderness map or a room that requires the skill. Treading water by staying in one place without moving is less tiring than moving in a given direction, but a careless character can still drown this way.

Your swimming skill and your species both determine how fast your character can swim. The poorer their swimming, the slower they will be, and the more likely they will accidentally swallow water. Rougher waters are more difficult to swim in than calm ones. Swamps also require some amount of swimming skill to traverse due to how much of water they contain.